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Abstract Background Cancer cachexia is associated with reduced body weight, appetite and quality of life (QOL) with no approved treatments. Growth hormone secretagogues like macimorelin have potential to mitigate these effects. Methods This pilot study assessed the safety and efficacy of macimorelin for 1 week. Efficacy was defined a priori as 1‐week change in body weight (≥0.8 kg), plasma insulin‐like growth factor (IGF)‐1 (≥50 ng/mL) or QOL (≥15%). Secondary outcomes included food intake, appetite, functional performance, energy expenditure and safety laboratory parameters. Patients with cancer cachexia were randomized to 0.5 or 1.0 mg/kg macimorelin or placebo; outcomes were assessed non‐parametrically. Results Participants receiving at least one of either macimorelin dose were combined (N = 10; 100% male; median age = 65.50 ± 2.12) and compared with placebo (N = 5; 80% male; median age = 68.00 ± 6.19). Efficacy criteria achieved: body weight (macimorelin N = 2; placebo N = 0; P = 0.92); IGF‐1 (macimorelin N = 0; placebo N = 0); QOL by Anderson Symptom Assessment Scale (macimorelin N = 4; placebo N = 1; P = 1.00) or Functional Assessment of Chronic Illness Therapy‐Fatigue (FACIT‐F; macimorelin N = 3; placebo N = 0; P = 0.50). No related serious or non‐serious adverse events were reported. In macimorelin recipients, change in FACIT‐F was directly associated with change in body weight (r = 0.92, P = 0.001), IGF‐1 (r = 0.80, P = 0.01), and caloric intake (r = 0.83, P = 0.005), and inversely associated with change in energy expenditure (r = −0.67, P = 0.05). Conclusions Daily oral macimorelin for 1 week was safe and numerically improved body weight and QOL in patients with cancer cachexia compared with placebo. Longer term administration should be evaluated for mitigation of cancer‐induced reductions in body weight, appetite and QOL in larger studies.

New Findings: What is the main observation in this case?Co‐administration of LGD‐4033 and MK‐677 increased body mass, lean mass and fat mass, while negatively impacting bone, serum lipids, liver enzymes, testosterone (total and free) and, probably, follicle‐stimulating hormone.What insights does it reveal?Our cross‐sectional data imply that these compounds might alter intramuscular androgenic hormone and receptor concentrations along with promoting muscular strength, when compared with previously published data from trained males. LGD‐4033, a selective androgen receptor modulator, and MK‐677, a growth hormone secretagogue, are being used increasingly amongst recreationally active demographics. However, limited data exist describing their effects on health‐ and androgen‐related biomarkers. The purpose of this case study was to determine changes in body composition and biomarkers during and after continued co‐administration of LGD‐4033 and MK‐677. We also aimed to examine muscular strength and intramuscular androgen‐associated biomarkers relative to non‐users. A 25‐year‐old male ingested LGD‐4033 (10 mg) and MK‐677 (15 mg) daily for 5 weeks. Blood and body composition metrics were obtained pre‐, on‐ and post‐cycle. One‐repetition maximum leg and bench press, in addition to intramuscular androgens and androgen receptor content, were analysed on‐cycle. We observed pre‐ to on‐cycle changes in body composition (body mass, +6.0%; total lean body mass, +3.1%; trunk lean body mass, +6.6%; appendicular lean body mass, +4.3%; total fat mass, +15.4%; trunk fat mass, +2.8%; and appendicular fat mass, +14.8%), bone (bone mineral content, −3.60%; area, −1.1%; and bone mineral density, −2.1%), serum lipid‐associated biomarkers (cholesterol, +14.8%; triglycerides, +39.2%; low‐density lipoprotein–cholesterol, +40.0%; and high‐density lipoprotein–cholesterol, −36.4%), liver‐associated biomarkers (aspartate aminotransferase, +95.8%; and alanine aminotransferase, +205.0%) and androgen‐associated biomarkers (free testosterone, −85.7%; total testosterone, −62.3%; and sex hormone‐binding globulin, −79.6%); however, all variables returned to pre‐cycle values post‐cycle, apart from total fat mass, appendicular fat mass, bone area, total cholesterol and low‐density lipoprotein–cholesterol. Follicle‐stimulating hormone was below clinical reference values on‐ (1.2 IU/L) and post‐cycle (1.3 IU/L). Intramuscular androgen receptor (−44.6%), testosterone (+47.8%) and dihydrotestosterone (+34.4%), in addition to one‐repetition maximum leg press and bench press (+39.2 and +32.0%, respectively), were different in the case subject compared with non‐users. These data demonstrate that LGD‐4033 and MK‐677 increase several body composition parameters, whilst negatively impacting bone and several serum biomarkers. Given the sparsity of data in recreationally using demographics, further research is warranted to elucidate the acute and chronic physiological effects of these anabolic agents. [ABSTRACT FROM AUTHOR]

An oral test supplement increases serum human growth hormone (hGH) levels after acute administration in healthy adults. We investigated the mechanism for the increase in hGH and the effect of continued daily administration of the test supplement on measures of physical fitness and sleep efficiency. In Study 1, serum triiodothyronine (T3) was measured in samples from a prior placebo-controlled, double-blind study in which 16 healthy participants received both placebo and the test supplement in a crossover design; treatment order was randomized, and treatments were separated by a 1-week washout. In Study 2, physical fitness (VO2 max) was measured at baseline and after 2 weeks of daily administration of the test supplement (N = 12 healthy participants). Study 3 assessed daily sleep onset latency and time awake during 3 weeks of daily administration of the test supplement (N = 15 healthy participants). A fall from baseline in T3 was observed with placebo (−6.1 ± 8.5 ng/dL, P = .01). Of note, the change in T3 was smaller with the test supplement (−3.3 ± 10.7 ng/dL, P = not significant) but was not statistically different from placebo. Mean VO2 max increased by 6% from baseline after 2 weeks (P = .02). Sleep-onset latency and time awake during the night were reduced from baseline to week 3 by 22% and 65%, respectively (P = .01 and P = .02). The conservation of T3 levels suggests that the mechanism for increased hGH secretion by the test supplement is through somatostatin inhibition. Furthermore, pilot studies indicated that daily administration of the supplement improved physical fitness and sleep efficiency from baseline, effects consistent with increased endogenous hGH release. Clinical Trial Registration No. NCT02987868. [ABSTRACT FROM AUTHOR]

The aquaculture sector has experienced rapid and important growth with the subsequent increase of feeding and nutritional issues for sustaining this activity, mainly related to the use of high quality, safe and environmentally friendly feed ingredients. The use of additives in aquafeeds has proven to be a suitable option to improve different productive indicators in farmed fish. In the present study, the effect of adding the GHRP-6 peptide, a ghrelin analog, to a commercial diet of gilthead sea bream (Sparus aurata) was studied at two proportions (100 or 500 μg/kg of feed). Both experimental diets show an increase in growth performance, as well as in feed efficiency after 97 days of experiment. The lower inclusion of GHRP-6 (100 μg/kg) results in a better aerobic metabolism, while the higher inclusion significantly increased plasma GH levels in agreement with the GH secretagogue effects of ghrelin. Similar growth outcome and differences between GHRP-6 levels in aerobic metabolism and GH stimulation suggest that improvements in culture performance by this peptide may occur through different mechanisms. Taken together, this compound can be considered as a viable dietary supplement for increasing production efficiency of sea bream aquaculture, although a better understanding of its dose-specific effects is still required.

Abstract A novel third channel catfish growth hormone secretagogue (ghrelin) receptor, GHS-R3a, gene was characterized. Identification and analysis of the genomic organization of channel catfish GHS-R3a revealed differences in exon/intron structure relative to the previously published GHS-R1a and GHS-R2a sequences. Amino acid sequence alignment of catfish GHS-R3a with -R1a and -R2a revealed 48 and 52% sequence identity, respectively. Phylogenetic analysis predicted a new clade of GHS-R3a receptors found only in fish, with representation in the teleost infradivisions Osteoglossomorpha, Clupeomorpha, and Euteleostei. In functional analyses, homologous catfish ghrelin increased intracellular Ca2+ concentration in human embryonic kidney (HEK) 293 cells stably expressing catfish GHS-R3a. On the contrary, intracellular Ca2+ concentration was unaffected by treatment with the synthetic growth hormone secretagogues GHRP-6 and hexarelin. Realtime PCR results indicated high expression of GHS-R3a in the brain and gonads, demonstrating tissue specificity among the catfish GHS-Rs. The effects of fasting and refeeding on all three ghrelin receptors were evaluated in catfish brain, pituitary, stomach, and Brockmann bodies. Most notably, GHS-R3a was the only receptor observed to significantly increase (2.9–6.3-fold) in brain, pituitary, and stomach within 4 days of fasting (P <.05). Stomach GHS-R1a also increased (P <.05) after 4 days; however, GHS-R2a was only elevated in brain and pituitary after refeeding for 1 week. Expression of all three ghrelin receptors were elevated (P <.05) in the Brockmann bodies after 2 weeks of fasting and returned to prefasting levels following refeeding. Together with the previously published characterization of GHS-R1a and -R2a, these results establish three ghrelin receptors, each altered by energy state, in channel catfish and add to the growing body of information on GHS-R evolution and function. Highlights • We identified and characterized the third channel catfish ghrelin receptor, GHS-R3a. • We firstly discovered a new clade of ghrelin receptors in bony fishes, which is not present in non-mammals and mammals. • This research describes a complex multi-tissue ghrelin/GHS-R system in channel catfish involved in maintaining homeostasis. [ABSTRACT FROM AUTHOR]

Background: Growth hormone secretagogues (GHS), among other factors, regulate the release of GH. The biological activity of the secretagogue peptide A233 as a promoter of growth and innate immunity in teleost fish has previously been demonstrated, but its role in the immune system of mammals is not well understood. Methods: The effect of the peptide was investigated in J774A.2 macrophage cells using a comparative proteomics approach after 6 and 12 h of peptide stimulation. Results: The functional analysis of differentially modulated proteins showed that A233 peptide treatment appears to promote activation and ROS-dependent cytotoxic functions in macrophages and enhanced expression of antiviral protein complexes such as MAVS. In accordance with this hypothesis, we found that A233 treatment enhanced superoxide anion production and the IFN-γ level in J774A.2 cells and mouse splenocytes, respectively, and reduced viral load in a dengue virus mouse model of infection. Conclusions: The growth hormone secretagogue A233 peptide promotes activation of ROS-dependent cytotoxic functions and exerts immunomodulatory effects that enable an antiviral state in a dengue virus mouse model. General Significance: The increase of IFN-γ level and the differential modulation of antiviral proteins by the A233 peptide suggest that the molecule could activate an innate immune response with a possible further impact in the treatment of acute and chronic diseases.

Capromorelin is a ghrelin receptor agonist that is FDA approved for appetite stimulation in dogs. The objective of this study was to evaluate the safety of daily oral administration of capromorelin to cats over a range of doses and for an extended period. Two randomized, controlled studies were conducted: in Study 1, cats (n = 6 per group) received placebo or capromorelin at a dose of 9, 15, 30 or 60 mg/kg once daily for 14 days; and in Study 2, cats received capromorelin at 6 mg/kg (n = 8) or placebo (n = 4) once daily for 91 days. Cats were evaluated using clinical observations and clinical pathology test results for both studies, with the addition of postmortem examination in Study 1 and measurements of growth hormone and insulin‐like growth factor 1 in Study 2. Abnormal clinical observations were limited to emesis, hypersalivation, lethargy/depression, head shaking and lip smacking, which occurred more frequently in the capromorelin‐treated groups than in the placebo group. There were no clinically relevant differences in clinical pathology test results between the capromorelin and placebo groups in either study. [ABSTRACT FROM AUTHOR]

Abstract: Growth hormone (GH) release is a process that is well regulated by several factors, including GH secretagogues. GH can mediate the regulation of the fatty acid level and composition. The aim of this study was to determine the effect of a synthetic GH secretagogue peptide (A233) on the growth and fatty acid composition in tilapia (Oreochromis niloticus). To address this objective, we administrated a diet supplemented with A233 to juvenile tilapia for 60 days. The group fed with a diet supplemented with 600 μg of A233 per kg of feed increased in weight (4.81 ± 0.09 g) and specific growth rate (2.49 ± 0.03%/day) compared to the control diet group (3.63 ± 0.08 g, 2.07 ± 0.04%/day; respectively) (p < 0.001). In the muscle, the total lipids for the control diet group were higher than that in the group fed with 600 μg of A233 per kg feed; however, no differences were detected in the liver. In both tissues, the patterns of fatty acid composition and content were generally similar, with some exceptions. Tilapia fed with 600 μg of A233 per kg of feed showed, in liver and muscle, a significantly higher composition and content of n‐3 polyunsaturated fatty acids (such as 20:5n‐3, 22:5n‐3, 22:6n‐3) and n‐3/n‐6 PUFA than animals fed with the control diet. To our knowledge, this is the first report on the the effects of natural or synthetic GH secretagogues (GHS) on fatty acid composition, implying an increase in the nutritional quality of the tilapia. [ABSTRACT FROM AUTHOR]

Abstract: Ghrelin is a hormone, secreted from cells in the stomach, which is important in the regulation of appetite and food intake in mammals. It exerts its action by binding to a specific G‐protein‐coupled receptor, the growth hormone secretagogue receptor 1a (GHS‐R1a) which is found in areas of the brain associated with the regulation of food intake. Ghrelin causes a release of growth hormone (GH) through binding to GHS‐R1a in the hypothalamus and pituitary gland. A class of compounds known as growth hormone secretagogues, or ghrelin receptor agonists, were developed for therapeutic use in humans for the stimulation of GH in the frail elderly, and have subsequently been studied for their effects on increasing appetite and food intake, increasing body weight, building lean muscle mass, and treating cachexia. Subsequent research has shown that ghrelin has anti‐inflammatory and immunomodulatory effects. This article reviews the basic physiology of ghrelin and the ghrelin receptor agonists, including the available evidence of these effects in vitro and in vivo in rodent models, humans, dogs and cats. One of these compounds, capromorelin, has been FDA‐approved for the stimulation of appetite in dogs (ENTYCE®). The data available on the safety and effectiveness of capromorelin is reviewed, along with a discussion of the potential clinical applications for ghrelin receptor agonists in both human and veterinary medicine. [ABSTRACT FROM AUTHOR]

Realizing the reported misuse of human growth hormone (GH), investigation of a safe alternative mechanism for increasing endogenous GH is needed. Several GH secretagogues are available, including GH-releasing peptides (GHRPs) GHRP-2 and GHRP-6, and the GH-releasing hormone analog, sermorelin (SERM). Insulin-like growth factor 1 (IGF-1) serves as a surrogate marker for GH. Here, the effect of GHRP/SERM therapy on IGF-1 levels is evaluated. A retrospective review of medical records was performed for 105 men on testosterone (T) therapy seeking increases in lean body mass and fat loss who were prescribed 100 mcg of GHRP-6, GHRP-2, and SERM three times daily. Compliance with therapy was assessed, and 14 men met strict inclusion criteria. Serum hormone levels of IGF-1, T, free T (FT), estradiol (E), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were evaluated. Mean (SD) age of the cohort was 33.2 (2.9) years, and baseline IGF-1 level was 159.5 (26.7) ng/mL. Mean (SD) duration of continuous GHRP/SERM treatment was 134 (88) days. Mean posttreatment IGF-1 level was 239.0 (54.6) ng/mL (p < .0001). Three of the 14 men were on an aromatase inhibitor and/or tamoxifen prior to treatment and another 4 men were coadministered an aromatase inhibitor and/or tamoxifen during treatment. Inhibition of E production or estrogen receptor blockade resulted in smaller increases in IGF-1 levels. GHRP/SERM therapy increases serum IGF-1 levels with strict compliance to thrice-daily dosing. The results suggest that combination therapy may be beneficial in men with wasting conditions that can improve with increased GH secretion. [ABSTRACT FROM AUTHOR]

A practical synthesis of capromorelin ( 1 ), a growth hormone secretagogue, is described that utilizes as a key step a crystallization-induced dynamic resolution (CIDR) of (±)-3a-benzyl-2-methyl-4,5,6,7-tetrahydro-2 H -pyrazolo[4,3- c ]pyridin-3(3aH)-one [(±)- 2 ] by L -tartaric acid salt formation, yielding ( R )- 2. L -tartaric acid in high chemical yield (>85%) and with diastereomeric excess (de) of ∼98%. Treatment of ( R )- 2. L -tartaric acid with ammonium hydroxide provided ( R )- 2 without loss of chiral purity. In situ generated ( R )- 2 was coupled with ( R )-3-(benzyloxy)-2-(2-( tert -butoxycarbonyl)-2-methylpropanamido)propanoic acid [( R )- 3 ] to give predominantly a single diastereomer of N -Boc-protected capromorelin [(1 R ,3a R )- 4 ]. This process was used to prepare bulk quantities of capromorelin from (±)- 2 to support preclinical toxicology studies. [ABSTRACT FROM AUTHOR]

Background: Dogs can suffer from inappetence caused by a variety of medical conditions. This may present as anorexia (complete loss of appetite), hyporexia (decreased appetite) or dysrexia (change in food preferences). A drug with a new mechanism of action, capromorelin, has potential to stimulate appetite in dogs. Capromorelin is a ghrelin receptor agonist, which mimics the action of endogenous ghrelin. It is a member of the growth hormone secretagogue (GHS) class of drugs. Capromorelin oral solution (ENTYCE®) was tested in healthy adult male and female Beagle dogs (n = 6 males and 6 females per group) for its effect on food consumption and body weight. A randomized, masked, placebo controlled study was conducted to measure the effects of a daily 3 mg/kg oral dose given over 4 days. Dogs were observed for clinical signs, physical examinations were completed prior to and at the end of treatment, and blood was drawn before and after treatment for evaluation of serum chemistry and hematology parameters. Results: Capromorelin was well-tolerated, with no abnormalities seen on physical examination or clinical pathology. Some dogs showed increased salivation. Capromorelin treated dogs had increased mean (±SD) food consumption compared to placebo treated dogs (60.55 ± 39.87% versus -11.15 ± 14.23% respectively, P < 0.001). Treated dogs also had increased mean body weights compared to placebo treated dogs (5.96 ± 1.76% versus 0.053 ± 1.14% respectively, P < 0.001). Conclusions: This study supports the effectiveness of capromorelin oral solution as an appetite stimulant in dogs. Treatment with the oral solution resulted in dramatic increases in appetite, as measured by food consumption, of over 60% compared to placebo. The drug was well tolerated. Capromorelin is the first ghrelin receptor agonist developed for appetite stimulation in any species, and represents a novel mechanism of action for this clinical use. [ABSTRACT FROM AUTHOR]